Kurdish authorities announced on Sunday the release of two Yazidi people, who were held in captive by Islamic State since 2014.

"Kurdish troops have released a pair, a young man and a woman, aged 18, after they were kidnapped by Islamic State in Tal Banat village in Nineveh's Sinjar district four years ago," Alghad Press website quoted the Kurdish governmental office in charge of Yazidi abductees as saying in a statement.

According to the statement, "strenuous efforts are currently exerted to release the remaining Yazidi victims from the Islamic State's grip."

In August 2014, Islamic State militants launched an offensive in northern Iraq, executing thousands of Yazidi men and elderly women and forcing 300,000 Yazidis to flee. IS also sold more than 6,000 women and children into slavery, subjecting them to systematic mass rapes that the UN and other countries have defined as genocide.

US-backed Kurdish forces drove IS out of Sinjar in November 2015, but few Yazidis have returned, and an estimated 3,500 remain in IS captivity in Iraq and Syria, according to Human Rights Watch.

The Islamic State group emerged in 2014 when it seized large swathes of territory in Iraq and Syria, declaring a plan to establish an Islamic "caliphate" from Mosul city.

However, Iraqi troops, backed by a U.S.-led international coalition, were able to defeat the militant group three years after it captured about a third of Iraq's territory.